networking: make skb_push & __skb_push return void pointers

It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.

Make these functions return void * and remove all the casts across
the tree, adding a (u8 *) cast only where the unsigned char pointer
was used directly, all done with the following spatch:

    @@
    expression SKB, LEN;
    typedef u8;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    @@
    - *(fn(SKB, LEN))
    + *(u8 *)fn(SKB, LEN)

    @@
    expression E, SKB, LEN;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    type T;
    @@
    - E = ((T *)(fn(SKB, LEN)))
    + E = fn(SKB, LEN)

    @@
    expression SKB, LEN;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    @@
    - fn(SKB, LEN)[0]
    + *(u8 *)fn(SKB, LEN)

Note that the last part there converts from push(...)[0] to the
more idiomatic *(u8 *)push(...).

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index a9fa6ee57e8f..da7427a41529 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -288,7 +288,7 @@ ieee80211_add_tx_radiotap_header(struct ieee80211_local *local,
 	unsigned char *pos;
 	u16 txflags;
 
-	rthdr = (struct ieee80211_radiotap_header *) skb_push(skb, rtap_len);
+	rthdr = skb_push(skb, rtap_len);
 
 	memset(rthdr, 0, rtap_len);
 	rthdr->it_len = cpu_to_le16(rtap_len);